It is known in the art of air conditioners and heat pumps that a condenser and an evaporator must be placed in communication with each other by means of shut-off valves and other devices designed to cause expansion of the refrigerant as the refrigerant flows from one component to another.
Specifically, in refrigerant systems operating in both the cooling and heating modes, two expansion devices may be incorporated into one system allowing for expansion of the fluid in either direction. A shut-off valve may also be incorporated into a system when there is a need to terminate refrigerant flow, such as for example, during servicing. The refrigerant system may also include a sampling port for detecting and measuring the pressure of the high-pressure refrigerant before the refrigerant enters the expansion device. Furthermore, the ability to easily interchange the expansion devices allows the degree of expansion to be selectively varied after installation of the shut-off valve.
Combining the shut-off valve, expansion devices and sampling device into one unit is desirable to reduce the complexity of a refrigerant system. However, known refrigerant systems lack a mechanism for sampling the liquid refrigerant before the liquid enters the expansion devices in both the cooling and heating modes. Therefore, a need exists for a shut-off valve that allows for sampling high-pressure liquid between two expansion devices.
Prior art dual restrictors utilize a labor intensive process of manually torch brazing the connecting tube to the shut-off valve body in order to protect expansion devices integrated within the body. It is desired to use a more cost efficient process of furnace brazing the tube onto the valve body. Therefore, a need exists for a shut-off valve having integrated expansion devices which will not be adversely affected by the furnace brazing process.